<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
  body > * {
        width: 980px;height: auto;margin: 0 auto;margin-top: 10px;
        border: 1px solid #000;padding: 5px;
  }
        header {height: 50px;}
        section {height: 300px;}
        footer {height: 30px;}
        section > * {height: 100%;border: 1px solid #000;float: left;}
        aside {width: 250px;}
         article {width: 700px;margin-left: 10px;}
    </style>
</head>
<body>
<header>header</header>
  <nav>nav</nav>
  <section>
    <aside>aside</aside>
    <article>article</article>
  </section>
  <footer>footer</footer>
</body>
</html>